NATO leaders on Tuesday in Ankara, before the arrival of Donald Trump, the U.S. president, will announce arms contracts worth tens of billions of dollars to show they have complied with Washington’s request to increase Europe’s defense spending. NATO Secretary General Mark Rutte said European countries have made a “significant” increase in defense budgets, and that this trend has been driven both by the threat from Russia and by direct pressure from Mr. Trump. NATO is also expected to announce the replacement of the older AWACS fleet with the Swedish GlobalEye system.